Mark Pennell sits at the helm of his time machine.Mark's Almanac is a 90-second time travel that highlights the world's history from the very serious to the sometimes sublime.
Mark's Almanac for April 20, 2021
It was on this date in 1999 that the Columbine High School massacre occurred near Littleton, Colorado. 12 students and one teacher would die in the shooting. At the time, it was the deadliest school shooting in U.S. history.